Study Guide: Human Diseases Chapters 1–3

Health

  • Defined by WHO as a state of complete physical, mental, and social well-being, not merely the absence of disease.

Homeostasis

  • The body's ability to maintain stable internal conditions despite external changes.

Signs vs. Symptoms

  • Signs are objective, measurable (e.g., fever).
  • Symptoms are subjective, felt by the patient (e.g., pain).

Pathology

  • The study of disease, including causes, development, and effects on the body.

Syndrome

  • A group of symptoms and signs that occur together and characterize a particular abnormality or condition.

Diagnosis Methods

  • Inspection.
  • Palpation.
  • Auscultation.
  • Imaging (X-ray, CT, MRI, ultrasound, PET).

Mammography

  • Used for early detection of breast cancer.
  • Recommended annually for women over 40.

Innate Immunity

  • Nonspecific defense mechanisms present from birth (e.g., skin, mucous membranes, inflammation).

Adaptive Immunity

  • Specific defense that develops after exposure to antigens, includes memory cells.

Inflammatory Response

  • Redness, swelling, heat, pain.
  • Involves histamine release, leukocytosis, and neutrophils.

Histamine

  • Chemical that causes vasodilation and increases vascular permeability during inflammation.

Complement System

  • Protein cascade that enhances immune response; activated by antibodies (e.g., C3, C4).

Antibodies

  • Immunoglobulins: IgM (first responder), IgG (long-term), IgA (mucosal), IgE (allergy), IgD (B cell activation).

Autoimmune Diseases

  • Immune system attacks self (e.g., Lupus, Rheumatoid Arthritis, Sjögren's Syndrome).

Pathogen

  • A microorganism that causes disease (bacteria, viruses, fungi, parasites).

Contagious Disease

  • Diseases spread through direct or indirect contact (communicable).

Epidemiology

  • Study of disease distribution, causes, and control in populations.

Incidence vs. Prevalence

  • Incidence = new cases.
  • Prevalence = total existing cases at a time.

Endemic Disease

  • Disease constantly present in a population (e.g., malaria in parts of Africa).

Epidemic

  • Sudden increase in cases in a specific area.

Pandemic

  • An epidemic that spreads across countries or continents (e.g., COVID-19).

Outbreak

  • Localized spike in disease cases that typically subsides over time.

Notifiable Diseases

  • Diseases required by law to be reported to health authorities (e.g., HIV, TB).

Fomites

  • Inanimate objects that can carry infectious agents (e.g., doorknobs, phones).

Disease Transmission

  • Horizontal (direct or indirect).
  • Vertical (mother to child).
  • Parenteral (needlestick).

Infection Control

  • Methods include vaccination, isolation, quarantine, and disinfection.

Nosocomial Infection

  • Hospital-acquired infections (e.g., MRSA, from healthcare workers or devices).

Syphilis

  • STD caused by Treponema pallidum.
  • Progresses from chancre (primary) to rash (secondary) to organ damage (tertiary).

HIV/AIDS

  • Virus that attacks immune cells.
  • Managed with antiretroviral therapy.
  • Transmitted via blood, sex, birth.

Gonorrhea & Chlamydia

  • Common bacterial STIs, often asymptomatic but can lead to serious reproductive complications.